|Year : 2020 | Volume
| Issue : 4 | Page : 346-350
Arterial thoracic outlet syndrome – The need for early detection and surgical correction and how to do subclavian artery repair without resection
Department of Vascular and Endovascular Surgery, Kauvery Hospital, Chennai, India
|Date of Submission||17-Jul-2020|
|Date of Acceptance||23-Jul-2020|
|Date of Web Publication||24-Dec-2020|
Department of Vascular and Endovascular Surgery, Kauvery Hospital, Chennai
Source of Support: None, Conflict of Interest: None
Objective: Arterial compression at the thoracic outlet is rarely diagnosed before embolization occurs. Decompression, embolectomy, and resection of the subclavian artery and interposition graft repair is the most common method of treatment. This is a retrospective analysis of a single surgeon experience with subclavian artery repair without resection for arterial thoracic outlet syndrome. Materials and Methods: Sixty limbs underwent surgery for arterial compression at the thoracic outlet in 57 patients over the last 29 years (1989–2018). There were 24 males and 33 females. The age group varied from 10 to 60 years. Thrombointimectomy and repair of the subclavian artery were done on 54 of the 57 symptomatic limbs. Three patients underwent prophylactic decompression of the thoracic outlet on the contralateral asymptomatic side. Results: Fifty-two patients had complete cervical rib, two had abnormal first rib, and three patients had fracture clavicle with nonunion. Fifteen patients presented with severe rest pain and pregangrenous changes in the finger tips. All the rest presented with ischemic changes of varying degrees in the upper limb. The duration of symptoms ranged from 2 to 300 days. All patients underwent decompression of the thoracic outlet in the form of scalenectomy and cervical rib or first rib resection. Thrombointimectomy and repair of the poststenotic dilatation without resorting to resection were done in 54 limbs. Only three patients required resection of the artery. One patient had end-to-end anastomosis and two others had interposition grafts. In addition, 43 patients had additional transbrachial embolectomy to clear the distal artery. Two patients had cervicodorsal sympathectomy. No patient underwent major amputation, but two patients required finger amputation. Palpable wrist pulse could be achieved in 45 patients. Patients were followed for an average of 2 years. Palpable pulse disappeared at 6-month follow-up in four patients. These four and another three patients with palpable pulse and the remaining 12 patients with no wrist pulse continued to have minor ischemic symptoms in the fingertips. Long-term follow-up did not reveal any aneurysm or stenosis at the subclavian repair site. Conclusion: Cervical rib though a congenital condition can remain asymptomatic till a later age. Arterial compression is rarely diagnosed before embolisation occurs. The distal artery may not be completely cleared of thrombi, and about 30% of the patients continue to suffer from ischemic symptoms even after successful surgery. Hence, all patients with complete cervical rib should be investigated and followed up with duplex scan for evidence of arterial compression. They should be advised prophylactic decompression when they develop duplex evidence of arterial compression. Intimectomy and subclavian artery repair produce good long-term results, and unnecessary resection of the subclavian artery should be avoided.
Keywords: Arterial thoracic outlet syndrome, cervical rib, thoracic outlet syndrome, subclavian artery
|How to cite this article:|
Natarajan S. Arterial thoracic outlet syndrome – The need for early detection and surgical correction and how to do subclavian artery repair without resection. Indian J Vasc Endovasc Surg 2020;7:346-50
|How to cite this URL:|
Natarajan S. Arterial thoracic outlet syndrome – The need for early detection and surgical correction and how to do subclavian artery repair without resection. Indian J Vasc Endovasc Surg [serial online] 2020 [cited 2021 Mar 1];7:346-50. Available from: https://www.indjvascsurg.org/text.asp?2020/7/4/346/304646
| Introduction|| |
Arterial compression at the thoracic outlet is rare. Embolization of the distal artery is the usual presenting symptom, and the diagnosis is rarely done before the onset of complications. Decompression by resection of the rib and repair of the subclavian artery and distal embolectomy produces good results if done early. Majority of the reports mention subclavian artery repair by resection of the artery and reconstruction by either end-to-end anastomosis or interposition graft. Intimectomy and in situ repair of the artery without resection can be done easily with good long-term results. This helps to avoid unnecessary mobilization of the artery and additional procedure for vein harvest. Delay in diagnosis and treatment leads to incomplete clearance of the distal artery, and many patients are left with chronically ischemic limb and significant disability. Hence, to prevent this serious complication, prophylactic decompression should be advised for patients with complete cervical rib with evidence of arterial compression.
| Materials and Methods|| |
Sixty limbs in 57 patients underwent surgery for arterial compression at the thoracic outlet in the last 29 years (1989–2018). There were 24 men and 33 women. Their age group varied from 10 to 60 years. Twenty of these patients were over the age of 40. Fifty-two patients had complete cervical rib, two had abnormal first rib [Figure 1]a and [Figure 1]b, and three patients had fracture clavicle with nonunion causing compression. Bilateral cervical rib was present in 15 of these patients. Three patients had duplex evidence of significant arterial compression on the asymptomatic contralateral side and underwent prophylactic surgery.
|Figure 1: (a) Bilateral cervical rib complete rib on the right side with a pseudoarthrosis incomplete rib on the left. (b) Abnormal first rib causing compression on the artery|
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|Figure 2: A 25-year-old female with complete cervical rib seen as a supraclavicular bulge (arrow). Finger gangrene due to embolization|
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All patients presented with upper limb ischemia. Fifteen patients presented with acute ischemia.
The remaining presented with various stages of acute-on-chronic ischemia. The average time delay from the onset of symptoms to surgery was 30 days (range: 2–300 days). Two patients had total occlusion of the subclavian artery did not have distal embolism, and they presented with chronic ischemia. They were symptomatic for 8–10 months before proper diagnosis was made. Those patients who had acute ischemia presented early. Even in them, Raynaud's symptoms had been present before the onset of acute ischemia.
Supraclavicular bony swelling was present in all patients. Prominent subclavian pulse or palpable aneurysm was present in most of them. Brachial pulse was absent in 36, and radial pulse was absent in all the patients on the symptomatic side. Ulcer, paronychia, cyanosis, and fingertip gangrene were the other signs. One patient presented with more extensive gangrene of the fingers [Figure 2]. All patients underwent a duplex study. Preoperative angiogram was performed (either invasive or computed tomography [CT] angiogram) in majority of the patients [Figure 3]a and [Figure 3]b. The youngest patient, a 10-year-old boy, had a saccular aneurysm of the subclavian artery. All the rest had fusiform dilatation of the poststenotic segment. The subclavian artery did not show any thrombus in the three patients on the contralateral asymptomatic side but showed poststenotic dilatation [Figure 4]a and [Figure 4]b. Intimal thickening and thrombus were seen in all the patients on the symptomatic side.
|Figure 3: (a) 23 yr old male. CT angiogram showing abnormal 1st rib causing compression of the subclavian artery (Yellow arrow points to 2nd rib, Green arrow points to 1st rib, Blue arrow points to clavicle). (b) The same patient showing distal embolization in both ulnar and radial arteries|
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|Figure 4: (a) A 23-year-old female. X-ray showing bilateral complete cervical rib. (b) Computed tomography angiogram showing subclavian artery thrombus with distal embolization on the right side and poststenotic dilatation on the asymptomatic left side|
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All patients were operated through a supraclavicular approach. Good decompression was performed first with scalenectomy and cervical rib or first rib resection. One patient with nonunion clavicle had the mid-segment of the clavicle resected and the other two had internal fixation done. After mobilization of the subclavian artery, the arterial thickening could be easily appreciated on one side of the artery mostly posteroinferior aspect. In all patients, longitudinal arteriotomy was done either at the middle of the plaque or along the anterior edge of the plaque. Thrombointimectomy was performed in 54 patients. If the arterial dilatation was mild, the arteriotomy was closed primarily. If the dilatation was large, the plaque was excised taking care to see that too much wall is not sacrificed so that there is no narrowing after closure [Figure 5]a, [Figure 5]b, [Figure 5]c, [Figure 5]d, [Figure 5]e. Resection and end-to-end anastomosis were required only for one patient. Interposition vein graft was done in one and poly tetra fluro ethylene graft in another. Both these patients had long-standing total occlusion of the subclavian artery and were not suitable for thrombointimectomy. Distal embolectomy was carried out successfully through the subclavian artery in only 14 patients. Forty-three patients had additional transbrachial embolectomy. At least one wrist pulse was restored in 45 patients. In 12 patients, both radial and ulnar pulses were not palpable but had collateral flow in distal arteries. In two of these patients, cervicodorsal sympathectomy was added in view of severe ischemia. These patients had residual chronic ischemic symptoms in the fingers. Three more patients continued to have Raynaud's symptoms in spite of having palpable radial pulse. In four other patients, palpable radial pulse disappeared at 6-month follow-up. These patients also continued to have paresthesia in the fingertips. These patients had adherent thrombus in the distal arteries [Figure 6]a, [Figure 6]b, [Figure 6]c, [Figure 6]d. Although they could be extracted by embolectomy, intimal damage caused it to reocclude. Two patients had presented with fingertip gangrene which needed partial amputation. No patient needed major amputation. All patients who had arterial repair were given antiplatelet drugs and were anticoagulated for a period of 3–6 months. The residual ischemic symptoms improved during follow-up, and hence, no patient needed distal bypass. Three patients who had prophylactic surgery on the contralateral asymptotic side underwent only decompression without arterial exploration.
|Figure 5: (a) Large poststenotic dilatation of the subclavian artery. (b) Arteriotomy along the edge of the plaque showing the thrombus adherent to the plaque in the posteroinferior wall. (c) Arterial wall after thrombointimectomy. (d) For tailoring, only the plaque is excised saving the normal wall. (e) Arteriotomy closed after tailoring. Normal diameter achieved|
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|Figure 6: (a) Operative arteriogram showing organized thrombus at brachial bifurcation. (b) Thrombectomy specimen. (c) Brachial artery bifurcation after thrombectomy. (d) Arteriotomy closed with a vein patch|
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One patient had pleural injury, one had transient phrenic nerve palsy, two had brachial neuralgia for 2 weeks, and two others had wound hematoma because of anticoagulation. There were no major complications or mortality. The average follow-up was for 2 years, and none developed any subclavian artery aneurysm or stenosis.
| Discussion|| |
Vascular compression at the thoracic outlet is very rare and is seen only in about 1%–5% of the patients., Interestingly, Maru et al. reported an incidence of 38% vascular complications in thoracic outlet syndrome (TOS) in young adults.
Arterial complications of TOS are due to long-standing compression of the subclavian artery by bony abnormalities at the thoracic outlet. The compression is usually at the interscalene triangle and less frequently at the costoclavicular space. The most common bony anomaly is the complete cervical rib.,, Complete cervical rib articulates with the first rib, and its anterior end may be bulbous or spatulate and cause arterial compression. Rarely, incomplete cervical rib can also cause arterial compression but more often is found to cause neurological compression. Rarely, anomalous first rib can also cause arterial compression [Figure 1]b. The anterior part of the first rib may be agenetic and can articulate with the second rib. In these patients, the rib is usually pulled up and causes arterial compression. Acquired causes such as malunited fracture clavicle with callus or tumor at the thoracic outlet can also cause arterial compression. Rarely, hypertrophied pectoralis minor tendon can cause compression of the axillary artery.
Narrowing at the interscalene triangle causes compression on the second part of the subclavian artery. Repeated shoulder movement causes trauma to the arterial wall causing an inflammatory response and thickening of the arterial wall leading to stenosis. The artery beyond develops poststenotic dilatation due to the turbulent flow. Sometimes, in long-standing compression, patients may present with aneurysm of the subclavian artery. Atheromatous plaque develops where the jet hits the poststenotic arterial wall. Platelet aggregation forms in this intimal lesion which embolizes distally and causes Raynaud's phenomenon. Majority of the emboli go through the radial artery and produce symptoms in the thumb and index fingers. Larger emboli can occlude major vessels and produce acute ischemia to the limb. Delay in diagnosis leads to distal artery getting progressively choked with microemboli which may even cause irreversible ischemia and limb loss. Sudden total thrombosis of the subclavian artery is also known. Two of our patients had total occlusion of the subclavian artery.
The diagnosis is usually made only after embolic complication occurs. In early stages, majority of the patients experience Raynaud's symptoms such as pain, color change, and coldness of fingertips. They may be mistaken for the more common collagen vascular disease more so when the wrist pulses are palpable. Recurrent emboli leave the limb chronically ischemic due to progressive obliteration of the distal arterial tree. Any further emboli or even a trivial trauma can precipitate gangrene. The patient will typically complain of work-related pain or pallor on elevation of the arm. Sometimes, patients may present with acute ischemia due to larger emboli in a major artery.
Duplex scan of the subclavian artery with the arm in the neutral position and after hyperabduction may show compression even in normal individuals. However, the presence of changes in the arterial wall in the poststenotic area (atheromatous plaque and thrombus) confirms the diagnosis. This study is most useful to check for any arterial compression in asymptomatic patients with complete cervical ribs. CT angiogram will show the compression as well as the distal circulation and is confirmatory.
Treatment of arterial complications of TOS is surgery. The surgery may have to be performed as an emergency or as a semi-emergency to prevent further embolization if the limb is severely ischemic. The surgery involves decompression of the thoracic outlet, repair of the subclavian artery, and clearing the distal tree of emboli. Arterial repair is undertaken only after completing the decompression. If there is no distal embolization, and the color Doppler of the poststenotic area does not reveal any intimal lesion or thrombus and the dilation is mild, it may be sufficient just to relieve the compression and not do arteriotomy. The intimal lesion will heal, and the dilation will regress with conservative treatment. However, it is safer to do longitudinal arteriotomy over the dilated part to actually inspect the intima. Closure of the longitudinal arteriotomy will automatically correct the mild dilation.
Surgical repair of the artery depends on the changes in the artery. Majority of the times the subclavian artery is resected, and end-to-end anastomosis or repair with interposition graft is done., This involves more extensive mobilization of the artery and additional incision for vein harvest. If the vein is not suitable due to size mismatch, synthetic grafts have to be used with its attending complications. Hence, all efforts should be made to repair the subclavian artery without resecting it. Intimectomy and limited segmental resection with or without patch closure have been tried but have not received widespread acceptance. There are very few reports of in situ repair of the subclavian artery avoiding resection of the artery. Understanding the pathophysiology of poststenotic dilatation will help us to plan the surgical repair without resection.
The poststenotic turbulence is not only due to the stenosis but also to angulation of the artery. The bony abnormality pushes the artery upward in the lower cervical region leading to its acute angulation. The abnormal shear force affects the arterial wall distending and rupturing components of media causing the vessel to dilate circumferentially. Intimal lesion can occur either at the site of compression or in poststenotic dilatation often at the site of impact of the poststenotic jet. The turbulent jet produces intimal damage to one side of the wall usually on the posteroinferior wall of the artery. The arterial wall is normal in the rest of the circumference. The thickening in the wall on the posteroinferior aspect of the poststenotic dilated segment can be easily appreciated by palpation. The arteriotomy should be made either in the middle of the plaque or at the edge of it. If the arterial dilatation is not much, intimectomy can be done and the artery can be closed after minimal tailoring of the edges. If the size of the artery is big, the plaque alone can be excised without sacrificing the normal artery and the artery can be closed primarily [Figure 7]a, [Figure 7]b, [Figure 7]c, [Figure 7]d. This will help to avoid unnecessary resection of the artery. This procedure has been done successfully in 54 of the 57 patients, and no dilatation or thrombosis has been noticed after long follow-up.
|Figure 7: (a) Large post stenotic aneurysmal dilatation of the subclavian artery. (b) Arteriotomy made at the middle of the palpable plaque. Thrombus is visible. (c) After thrombointimectomy. (d) Arteriotomy closure after excising the plaque and tailoring the dilatation. Normal lumen achieved|
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Larger dilatation or aneurysm of the artery will need resection of the affected segment. Before closure, a Fogarty embolectomy catheter is passed distally to extract the distal emboli. The brachial artery needs to be explored at the elbow when the embolus in the distal artery could not be completely cleared through the subclavian artery. Operative angiogram helps to identify residual emboli [Figure 6]. Sometimes, radial or ulnar artery has to be explored at the wrist to clear residual emboli. Thrombolytic agents can be infused into the distal artery to thrombolyse the adherent clot. Distal embolectomy may not be complete if the embolus is old and adherent. Bypass surgery to the patent segment of the artery may be needed for limb salvage. However, the results of bypass to the brachial artery in TOS have been reported to be poor in view of distal artery disease. It is better to delay the bypass after initial surgery since the embolectomised vessel can sometimes reocclude due to intimal damage as happened in four patients in this series. Usually, the subsequent progressive development of a collateral circulation in the limb will ensure a satisfactory functional result, and severe ischemia is rare. Some have even advocated only anticoagulation for distal artery thrombus instead of intervention for the same reason. If the limb is severely ischemic and the distal artery cannot be cleared fully, cervicodorsal sympathectomy may be added as an adjuvant procedure. In spite of best efforts, nearly 20%–30% of the patients can have residual ischemic symptoms causing disability but not limb-threatening ischemia. Angiogram [Figure 8] shows multiple digital arteries occluded.
|Figure 8: Palpable pulse but symptomatic due to small vessel occlusion. Angiogram shows that radial artery is occluded at wrist and multiple digital arteries are blocked|
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Recently, arterial TOS with subclavian aneurysms has been managed with rib resection and endovascular stent grafts. Risks of stent compression, fracture, restenosis, and thrombosis may be significant, and endovascular treatment may not be an appropriate choice in these young patients.
The outcome of the treatment depends on the status of the distal artery. Hence, early diagnosis and surgery are important. Unfortunately, patients with thoracic outlet obstruction and arterial compression are rarely diagnosed before the onset of embolization. More than 25% of our patients had presented with severe ischemia. Moreover, cervical rib can cause arterial compression even at later age, as was seen in this series. Hence, it may be advisable to do duplex scan in all patients with complete cervical rib to identify the presence of arterial compression and offer prophylactic decompression if there is radiological evidence of compression and changes in the arterial wall. Even those with no evidence of arterial compression need to be followed up for long because arterial compression can develop at any age. Twenty of our patients were over the age of 40 when they developed arterial occlusion. In a meta-analysis of 141 studies (n = 77,924 participants), cervical rib was significantly more prevalent in patients with TOS than in healthy individuals, with pooled prevalence estimates of 29.5% and 1.1%, respectively. The analysis showed that 51.3% of the symptomatic patients with cervical rib had vascular TOS and 48.7% had neurogenic TOS. Hence, patients with complete cervical rib should be followed regularly with duplex scan. Unfortunately, patients who are asymptomatic are reluctant to undergo prophylactic surgery. Only those patients who developed the problem on one side were ready to undergo surgery for the symptomatic side.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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